1. Field
The following description relates to a field of communication systems, and more particularly, to timing synchronization in a wireless communication system.
2. Description of Related Art
Receivers, such as a super regenerative receiver (SRR), are ultra low power radio receivers for low data rate applications. A basic structure of the SRR includes an antenna, a low noise amplifier (LNA), a super regenerative oscillator (SRO), an envelope detector (ED), an automatic gain control (AGC), a quench waveform generator, and a baseband filter (BBF). The operation principle of the SRR is based on a repeated build-up and decay of self-generated oscillations in the SRO having a frequency near radio frequency (RF) signal frequency intercepted by the antenna. The SRR is typically used in low power body area networks, remote control systems, such as garage door openers, robots, model ships, airplanes, short distance telemetry, and wireless security.
In general, frequency selectivity of the SRR is directly affected by an over quenching rate (OQR) of a quench signal. Currently, each data symbol is oversampled by a quench signal operating at a quench rate considerably higher than a data rate. This translates into relatively low frequency selectivity and an equivalent noise bandwidth that is much larger than the signal bandwidth. Thus, the SRR may be easily affected by out-of-band interference. Hence, it is desirable to maintain the OQR as low as possible. However, a higher OQR is needed to ensure that outputs are obtained for each incoming pulse envelope in the SRR. From these outputs, a fractional sample rate is chosen to maximize overall energy capture of an incoming signal. In order to improve an interference rejection, a lower OQR is required, but a higher OQR is necessary to improve the synchronization performance of the SRR.